Note: There is no mobile power comes with the backpack inside.

If you want to use External USB Charge Function, you have to do as follows:

1.Buy a mobile power 

2.Connect your mobile power with the USB interface inside the backpack  

3.Connect your phone with the USB interface outside the backpack

4.Charging begins.

There are 2 kinds of mobile power in the market.

1:Plug in your phone, you can start charging

2:Plug in your phone also need to press button of mobile power then start charging

To cope with this backpack, we suggest purchase of the first mobile power.